Introduction:. Varus alignment of the knee is common in patients undergoing unicondylar knee replacement. To measure the geometry and morphology of these knees is to know whether a single unicondylar knee implant design is suitable for all patients, i.e. for patients with varus deformity and those without. The aim of this study was to identify any significant differences between normal and varus knees that may influence unicondylar implant design for the latter group. Methodology:. 56 patients (31 varus, 25 normal) were evaluated through CT imaging. Images were segmented to create 3D models and aligned to a tri-spherical plane (centres of spheres fitted to the femoral head and the medial and lateral flexion facets). 30 key co-ordinates were recorded per specimen to define the important axes, angles and shapes (e.g. spheres to define flexion and extension facet surfaces) that describe the femoral condylar geometry using in-house software. The points were then projected in sagittal, coronal and transverse planes. Standardised distance and angular measurements were then carried out between the points and the differences between the morphology of normal and varus knee summarised. For the varus knee group, trends were investigated that could be related to the magnitude of varus deformity. Results:. Several significant differences between normal and varus knees were found, but most of these were small differences unlikely to be clinically significant or have an influence on implant design. However, two strong trends were observed. Firstly, the version of the femoral neck was significantly less for patients with varus knees (mean difference 9°; p < 0.05). The second trend was a significant difference in the sagittal morphology of the medial condyle. The kink angle, the angle formed by the intersection of the circles fitted to the flexion and extension facet surfaces, and their centres (Figure 1) was either absent or small in normal knees (mean 1°). An absent kink angle occurs when the circle defining the flexion facet surface lies within or makes a tangent to the circle defining the extension facet. However, for varus knees, the mean kink angle was 9°, with positive correlation with the angle of varus deformity (Figure 2). Discussion:. Varus knees have a significantly larger kink angle than normal knees, influencing the relative positions of the flexion and extension facet spheres that define the medial condylar geometry, contributing to the commonly observed ‘flattening’ of the medial condyle in the sagittal plane. Varus knees are also associated with significantly less anteversion of the femoral neck. It has been shown that reduced femoral neck anteversion causes increased loading of the medial condyle [1], and our results support this finding. The data generated in this study will feed further biomechanical testing to investigate the influence of kink angle and femoral neck version on the kinematics and load distribution in the varus knee

Introduction. Varus alignment in total knee replacement (TKR) results in a larger portion of the joint load carried by the medial compartment. [1]. Increased burden on the medial compartment could negatively impact the implant fixation, especially for cementless TKR that requires bone ingrowth. Our aim was to quantify the effect varus alignment on the bone-implant interaction of cementless tibial baseplates. To this end, we evaluated the bone-implant micromotion and the amount of bone at risk of failure. [2,3]. Methods. Finite element models (Fig.1) were developed from pre-operative CT scans of the tibiae of 11 female patients with osteoarthritis (age: 58–77 years). We sought to compare two loading conditions from Smith et al.;. [1]. these corresponded to a mechanically aligned knee and a knee with 4° of varus. Consequently, we virtually implanted each model with a two-peg cementless baseplate following two tibial alignment strategies: mechanical alignment (i.e., perpendicular to the tibial mechanical axis) and 2° tibial varus alignment (the femoral resection accounts for additional 2° varus). The baseplate was modeled as solid titanium (E=114.3 GPa; v=0.33). The pegs and a 1.2 mm layer on the bone-contact surface were modeled as 3D-printed porous titanium (E=1.1 GPa; v=0.3). Bone material properties were non-homogeneous, determined from the CT scans using relationships specific to the proximal tibia. [2,4]. The bone-implant interface was modelled as frictional with friction coefficients for solid and porous titanium of 0.6 and 1.1, respectively. The tibia was fixed 77 mm distal to the resection. For mechanical alignment, instrumented TKR loads previously measured in vivo. [5]. were applied to the top of the baseplate throughout level gait in 2% intervals (Fig.1a). For varus alignment, the varus/valgus moment was modified to match the ratio of medial-lateral force distribution from Smith et al. [1]. (Fig.1b). Results. For both alignments and all bones, the largest micromotion and amount of bone at risk of failure occurred during mid stance, at 16% of gait (Figs.2,3). Peak micromotion, located at the antero-lateral edge of the baseplate, was 153±32 µm and 273±48 µm for mechanical and varus alignment, respectively. The area of the baseplate with micromotion above 40 µm (the threshold for bone ingrowth. [3]. ) was 28±5% and 41±4% for mechanical and varus alignment, respectively. The amount of bone at risk of failure at the bone-implant interface was 0.5±0.3% and 0.8±0.3% for the mechanical and varus alignment, respectively. Discussion. The peak micromotion and the baseplate area with micromotion above 40 µm increased with varus alignment compared to mechanical alignment. Furthermore, the amount of bone at risk of failure, although small for both alignments, was greater for varus alignment. These results suggest that varus alignment, consisting of a combination of femoral and tibial alignment, may negatively impact bone ingrowth and increase the risk of bone failure for cementless tibial baseplates of this TKR design

Introduction. Varus positioning of cemented ‘composite beam’ stems is associated with increased risks of aseptic loosening and stem fracture. We investigated whether the incidence of varus malalignment of the Exeter polished, double taper design in a multicentre prospective study adversely affected outcome after total hip replacement (THR). Materials & Methods. A multicentre prospective study of 1189 THR was undertaken to investigate whether there is an association between surgical outcome and femoral stem malalignment. The primary outcome measure was the change in the Oxford hip score (OHS) at five years. Secondary outcomes included the rate of dislocation and revision, stem subsidence, quality of cementing. 938 (79.89%) were followed-up at five years. Results. 44 from a total of 1189 femoral stems (3.7%) were implanted in varus (=5° to the femoral axis). Pre-operative demographics and OHS were similar in both groups (p>0.05). Varus implantation was commoner after posterior than anterolateral approach (p< 0.001). Differences in the presence of femoral radiolucency, stem subsidence and quality of cement mantle were not significantly different (p>0.05). There was no difference in absolute OHS or OHS gain between the groups (neutral, mean = 40; varus, mean 40, p = 0.45, OHS gain neutral: 24, varus: 23, p=0.46). Differences in dislocation (p=0.54) or revision rates (p=0.35) were not significant. Conclusion. This study provides evidence that the Exeter stem may be tolerant of varus malalignment, both in terms of patient reported outcome and complication rate up to five years following surgery. Establishing whether aseptic loosening will be more common in the varus group will require longer follow-up

Introduction. Varus malpositioning of femoral stems has been recognised as a poor prognostic feature with regard to loosening and failure of cemented composite beam implants, but there have been no published results of the long-term effect on taper-slip designs. Objectives. To determine the results of varus placement of a polished triple tapered femoral stem. Methods. We have prospectively analysed the results of 350 consecutive polished triple-tapered C-Stem implants performed on 322 patients between March 2000 and July 2004, using a standard posterior approach and Palacos-R cement. All patients underwent annual clinical and radiological review. Results. The average duration of follow-up in surviving patients is 140 months (120–172 months). There were 49 femoral implants in 49 patients implanted with more than 5 degrees of varus (14%) with respect to the long axis of the femur, and 14 in 14 patients in more than 5 degrees of valgus (4%). Alignment within 5 degrees of neutral was achieved in 82% of cases. The average age in the varus group was 69.2 years (41–92), which was higher than in the neutral group (67.4 years: 25–89), more patients were male (49% v 36%) but the average BMI was similar (29 v 28). The average duration of follow-up was the same. There was only one re-operation in the varus group, which was a revision for deep infection. There was one dislocation successfully treated by closed reduction and one acetabular component is currently loose. In the neutral group there have been four dislocations, one of which required application of a PLAD; five revisions for aseptic loosening of the acetabular component associated with high wear rates, with a further three currently being loose; four intra-operative, undisplaced fractures of the greater trochanter; two peri-prosthetic femoral shaft fractures treated by internal fixation and two temporary nerve palsies. There has been no aseptic loosening of the femoral components in either group. Subsidence of the femoral stem within the cement mantle was noted in 96% of the entire series. There was no significant difference between the groups with respect to the degree of subsidence. In the varus group 78% subsided less than 2mm compared to 75% in the neutral group. None of the femoral implants in either group subsided more than 4mm and none demonstrated evidence of aseptic loosening or negative bone remodelling. Conclusion. Varus implantation of the femoral component was more common in older, male patients, but there was no increased risk of subsidence or loosening at a minimum follow-up of ten years

Introduction

John Insall described medial release to balance the varus knee; the release he described included releasing the superficial MCL in severe varus cases. However, this release can create instability in the knee. Furthermore, this conventional wisdom does not correct the actual pathology which normally exists at the joint line, and instead it focuses on the distal end of the ligament where there is no pathology.

We have established a new protocol consisting of 5 steps to balance the varus knee without releasing the superficial MCL and we tried this algorithm on a series of 115 patients with varus deformity and compared it to the outcome with a similar group that we have performed earlier using the traditional Insall technique.

The concept of constitutional varus and controversy regarding placing the total knee arthroplasty (TKA) in a neutral versus physiologic alignment in varus osteoarthritic (OA) patients is an important current discussion. However, the physiologic mechanical alignment of a varus OA knee is unknown and the relative contribution of the femur and tibia to the mechanical axis is unknown. The goal of this study was to determine and analyse the physiologic mechanical axis of medial OA knees.

Plain radiographs of the knee and full-leg standing radiographs of 1558 patients were reviewed for inclusion criteria; 313 patients with a non-arthritic knee and a contralateral varus end-stage OA knee were analysed in the coronal plane. The Hip-Knee-Ankle (HKA), Condylar-Hip (CH)(femoral), Condylar-Plateau (CP) (intra-articular) and Plateau-Ankle (PA)(tibial) angles were measured for both the arthritic and non-arthritic/physiologic knee. The relationship and contribution of all angles was analysed for every 2° degrees of progressive varus: from 4° valgus to 8° varus. The proportion of patients with constitutional varus was also determined for the sample population and correlated with increasing HKA.

The mean CH (femoral) angle was valgus in all groups and decreased with progressive varus alignment (p< 0.0001), ranging from 3.8° ± 1.0° with HKA of 2–4° valgus, to 0.1° ± 1.5° with HKA of 6–8° varus. The mean PA (tibial) angle was varus in all groups and decreased from valgus to progressively varus alignment (p p<0.0001), ranging from 0.78° ± 1.4° with HKA 2–4° valgus, to 5.6° ± 1.9° with HKA 6–8° varus. The CP angle showed no difference between all groups (p=0.3). Forty five percent of males and 22% of females with arthritic HKA in varus alignment were found to have constitutional varus.

Correlation of unilateral arthritic knees to the unaffected, physiologic aligned knee using full-leg radiographs indicates that it may be possible to understand the patient's physiologic, pre-arthritic coronal plane alignment. The mechanical axis of physiologic knees in a unilateral varus OA population demonstrates a variable contribution of the femur (CH) and tibia (PA) from overall valgus to varus alignment. In addition, a significant proportion of the sample population possessed constitutional varus. This may provide important information regarding the placement of physiologic TKA's and direct future research questions.

Background:. Varus or Valgus malpositioning of tibial prosthetic components in total knee replacement (TKR) surgery may lead to early failure due to increased polyethelene wear, soft tissue imbalancing, aseptic loosening and eventually revision surgery. Therefore, the clinical success of total knee arthroplasty (TKA) correlates with good component alignment. Conventional methods of coronal tibial alignment result in an acceptable range of prosthetic alignment in relation to the anatomical axis (tibial tangent angle). The measurement ranges from 90° ± 3°, but literature quotes that there is up to 27% of cases with coronal tibial alignment deviation of greater than 3°. Many studies show that the use of conventional intramedullary rod alignment versus extramedullary rod alignment gives similar results. The tibial alignment and overall prosthetic alignment in TKA has improved remarkably by using computerized navigation assisted surgery (CAS), with tibial tangent angle of 90° ± 3 in up to 97% of cases. However, the success of accurate tibial and femoral alignment depends on the surgeon and the data fed to the computer. Also long term results on survival rates of TKR using CAS is still pending. It is clear that assessing tibial alignment (ie. anatomical axis) with whatever method used faces challenges which will affect the tibial bony cuts and the final tibial tangent angle. To achieve a 90° tibial cut in relation to the anatomical axis we made use of fluoroscopy intra-operatively to assess the anatomical axis of the tibia and the correct alignment of the tibial cutting block. Methods:. TKR's were performed on 36 consecutive patients over a 4 month period. The aim was to assess the coronal tibial alignment of the tibial component intra-operatively using fuloroscopy. A conventional manual extramedullary alignment rod with its tibial cutting block was used and the final positioning was confirmed with an image intensifier. The tibial cutting block must be at 90° to the anatomical axis of the tibia. The rest of the TKR procedures were performed as routinely described. Post-operative radiographs were taken on the same day as the surgery and again at six week follow up visit when the tibial tangent angle was measured. Results:. The coronal tibial angulation was consistent at 0° in 32 knees with a 1°–2° deviation in 4 knees. Conclusion:. We conclude that the use of fluoroscopy intra-operatively can improve the tibial component alignment and thus decrease the cumulative errors which have significant and dramatic effects on the function and the longevity of the total knee prosthesis

Introduction. By all developments of new technologies on the improvement of the Total Knee implantation, the discussion about the optimum Alignment is in full way. Besides, is to be considered, that Alignment contains not only static, but also dynamic factors and beside the frontal plan also the sagittal plan as well as in particular the rotation in femur and tibia have a great importance for the outcome after TKR. However, beside the bone alignment, the kapsulo-igamentous structures also play an important role for the results after TKR. If a Varus-Malalignment was valid, in the past the „older” literature described it as a big risk factor for pain, less function and durability. However, in the present literature, we discuss more and more about the optimum Alignment during TKR. In particular, newer publications show no interference of the durability with coronar Alignment also outside from 3 °, also the score results and patient's satisfaction seem to deliver no worse results with slight untercorrection of the varus alignment. Some publications described even better score results and Patient satisfaction with slight untercorrection. Condition for it is probably an exact balancing of the extension and flexion gap. Material and method. With a new developed instruments it was examined with a tibia and extensions-Gap-First-Technique, to what extent a correction of the AMA opposed after digital planning within from 3 ° in distal femur a balancierung of the extension gap could be reached under avoidance of 3° releases with a varusarthritis oft the knee. 103 directly knee arthroplasties following on each other were selected with Varus-OA without exclusion criteria. Surgical technology. Midvastus-Approach, mostly in LIS technology. Besides, tibial 1–2 ° release and the following resection of the exophytes medial, lateral and intercondylar. External adjustment of the proxima tibia cut, place adjustable (Varus/Valgus, Slope) cutting block, control of the varus-(valgus position and slope after Fixation and if necessary postcorrection of these parameters. Resection of the proximal tibia. Next intramedullar adjustment of teh ditals femur cut according digital planning and fixation the adjustable/Varus/Valgus) cutting block for the distal femur resection. Insert the the ligament balancer between the promiumal tibia cut and the the dital femur in extension and examination of the parallelism between prox. Tibia and planned distal femur resektion with the same tension medial and lateral. If necessary correction of the cutting block within 3 ° to the achievement of a balanced extension gap, otherwise further releases necessary to create a balanced extension gap. Distale Femurresektion. Insert the the ligament balancer again between the promimal tibia cut and the the posterior femur condyles in 90° flexion with the same tension medial and lateral. Next step is to transfer the proximal tibia cut on distal Femur to determine femur rotation in gap balance technology. Fixation of the new developed sizing instrumet, final definition of the implant size of the femur according anterior and posterior referencing to avoid undercuts or overstuffing anterior and a reconstructi the posterior offset. Drilling of the admission holes for the 4 in 1 cutting block and at first posterior re section with following resection of posterior exophytes and the possibility of a posterior capsule release. Adapt the extension gap on the flexion gap by means of modular spacer blocks and perhaps necessary postresection oft he distal femur. Now realisation of the remaining femoral cuts with the 4 in 1-cutting block. Results. With 102 of 103 knee prosthesis implantations with Varus-OA a balancing of the extension gap could be realized, outgoing by the presurgical planning with max. 3 ° corrections on the distal femur cut. Only in a 1 case, a 3° release was necessary to achieve a balanced extension gap. The rotation according the posterior condyles with 102 within 3 ° correctable VarusOA lay between 0 and 8 ° with a frequency summit between 4 and 6 °. Summary. With the described Surgical technology by use a ligament tensioner and new developed instruments the balancing of the extension gap with slight to avarage medial release could be carried out in nearly all cases, so that the rotation could take place in these cases also in Gap-balance technology. Therefore it is possible with this technology beside a bone-saving TKR also sparing the capsulo-ligamtous structures. This thereby still wins on importance, that after newer literature data the kapsulo-ligamentous structures show a more physiological tension, in contrast to the correction to the neutral position, with light untercorrection of the preexistently varus deformity. In a projected prospektiv multicenter study we like to find answers to the questions about constitutional or residual Varus-Alignment after TKR in Varus-OA. Further question is if we can also compiled a sure zone within which an untercorrection is admissible

Femoral components used in total hip arthroplasty (THA) rely on good initial fixation determined by implant design, femoral morphology, and surgical technique. A higher rate of varus alignment may be of specific concern with short stem implants. Varus placement in uncemented femoral components has been proven not to be detrimental to clinical function; though long-term bone remodeling secondary to varus placement remains unknown. The goal of this study was to compare the clinical and radiographic outcomes in patients who underwent THA with one of two uncemented short stem metaphyseal engaging implants at minimum two-year follow-up. A review of 105 patients (average age 65 years; BMI 29 kg/m. 2. ) who underwent a total of 109 primary THAs using the ABG II short stem femoral implant (Stryker, Mahwah, NJ), and 160 hips in 149 patients (average age 70 years; BMI 28 kg/m. 2. ) who underwent primary THA using the Citation stem (Stryker, Mahwah, NJ). The same surgeon (SDS) performed all surgeries through a less invasive posterolateral approach. Pre-operative and post-operative Harris Hips Scores (HHS) and WOMAC scores were collected. Digital radiograph analysis was performed including measuring the stem alignment relative to the femoral shaft. A stem placed with greater than 5 degrees of varus was considered to be in varus. There was no significant difference in demographics (age, gender or BMI) or pre-operative HHS and WOMAC scores between the two groups. Follow-up HHS was 90 (range 63–100) and 94 (range 70–100) for the ABG II and Citation groups, respectively. Follow-up WOMAC scores were 10 (range 0–24) and 6 (range 0–43) for the ABG II and Citation groups, respectively. There was no statistically significant difference in any of the scores between the two groups (p>0.05). When looking at AP radiographs for postoperative intramedullary alignment, none of the ABG II implants were placed in varus (>5°), while a small number (4.9%) of Citation implants were implanted in varus alignment. No significant difference was observed in the alignment between the two groups (p>0.05). Average post-op alignment with the ABG was 1.10° (range −4.7–4.9°) and 0.88° (range −4.5–8.9°) with the Citation. The clinical results associated with the use of these stems in patients of all ages and bone types have been identical to those achieved by uncemented stems of standard length. Both implants in this study had excellent clinical and functional results in primary THA after a minimum 24-month follow up. In addition, postoperative radiographic analysis demonstrated that these stems can be reliably and reproducibly placed in neutral alignment despite their short length. The lateral flare on the Citation implant led to a greater number of implants in varus alignment, potentially affecting offset and leg-length, yet the relative increased incidence compared to the ABG II was not significant. Further research is needed in designing implants that optimize proximal femoral contact while maintaining alignment and overall hip kinematics

Introduction

Angular deformities of the distal femur can be corrected by opening, closing and neutral wedge techniques. Opening wedge (OW) and closing wedge (CW) are popular and well described in the literature. CW and OW techniques lead to leg length difference whereas the advantage of neutral wedge (NW) technique has several unique advantages. NW technique maintains limb length, wedge taken from the closing side is utilised on the opening side and since the angular correction is only half of the measured wedge on either side, translation of distal fragment is minimum. Leg lengths are not altered with this technique hence a useful technique in large deformities. We found no reports of clinical outcomes using NW technique. We present a technique of performing external fixator assisted NW correction of large valgus and varus deformities of distal femur and dual plating and discuss the results.

Introduction

Studies have shown that dissatisfaction following TKA may stem from poor component placement and iatrogenic factors related to variability in surgical execution. A CT-based robotic assisted system (RA) allows surgeons to dynamically balance the joint prior to bone resection. This study aimed to determine if this system could improve TKA planning, reduce soft tissue releases, minimize bone resection, and accurately predict component size in varus knee.

Background

Constitutional knee varus increases the risk of medial OA disease due to increase in the knee adduction moment and shifting of the mechanical axis medially.

Hueter-Volkmann's law states that the amount of load experienced by the growth plate during development influences the bone morphology. For this reason, heightened sports activity during growth is associated with constitutional varus due to added knee adduction moment. In early OA, X-rays often show a flattened medial femoral condyle extension facet (EF). However, it is unknown whether this is a result of osteoarthritic wear, creep deformation over decades of use, or an outcome of Hueter-Volkmann's law during development. A larger and flattened medial EF can bear more weight, due to increased load distribution. However, a flattened EF may also extrude the meniscus, leading meniscus degeneration and joint failure.

Therefore, this study aimed to investigate whether varus knees have flattened medial EFs of both femur and tibia in a cohort of patients with no signs yet of bony attrition.

Incidence of Congenital talipes equino varus [CTEV] is 1 to 2 per 1000 birth, Out of all cases 20% cases are Non-idiopathic. The management of non-idiopathic CTEV, however, continues to be challenging due to Rigidity, Poor skin condition, Bony changes, Vascularity and Associated congenital abnormalities. In recent literature, short term results of Ponseti method for correction of non-idiopathic CTEV have been encouraging. As Ponseti method decreases the severity of deformity and hence decreases the need for extensive surgery.

The aim of current study is to evaluate the results of Ponseti method in Non-idiopathic CTEV. Total 7 children below the age of one year with Non idiopathic clubfoot presented to us in the duration of 2013 to 2015 who were treated by us. The cases included are Streeters Dysplasia with congenital constriction rings 3, Arthrogryposis multiplex congenita with Developmental dysplasia of hip 2, Arthrogryposis multiple congenita spina Bifida 1, Pierre Robinson Syndrome with Ichthiosis 1. Initially all the patients treated with Ponseti casting technique and scoring was done using modified pirani scoring. At an average we could correct the foot from Pirani 7 to 2.5 with a relapse in 4 patients. 2 patients were treated again by Ponseti's method with success while treatment was discontinued in 2 feet.

We recommended Ponseti's technique in Syndromic clubfoot as an non-surgical initial modality with good results given. The final outcome may depend more on the underlying condition than the CTEV.

Aims

The aims of this prospective study were to determine the effect of osteophyte excision on deformity correction and soft- tissue gap balance in varus knees undergoing total knee arthroplasty (TKA).

Introduction

Acquiring adaptive soft-tissue balance is one of the most important factors in total knee arthroplasty (TKA). However, there have been few reports regarding to alteration of tolerability of varus/valgus stress between before and after TKA. In particular, there is no enough data about mid-flexion stability. Based on these backgrounds, it is hypothesized that alteration of varus/valgus tolerance may influence post-operative results in TKA. The purpose of this study is an investigation of in vivo kinematic analyses of tolerability of varus/valgus stress before and after TKA, comparing to clinical results.

Introduction

The deformity in osteoarthritis (OA) of the knee has been evaluated mainly in the frontal plane two dimensional X-ray using femorotibial angle. Although the presence of underlying rotational deformity in the varus knee and coexisting hip abnormality in the valgus knee have been suggested, three dimensional (3D) deformities in the varus and valgus knee were still unknown. We evaluated the 3D deformities of the varus and valgus knee using 3D bone models.

Ligament release in knee arthroplasty can be limited with accurate placement of implants, correct sizing and anatomic geometry of the implants. Still, in some instances a release of the medial collateral ligament can be necessary. In the proposed minimally invasive technique, multiple punctures in the MCL are made, using an 19-gauge needle, in order to progressively stretch the MCL until a correct ligament balance is achieved. This technique requires no additional soft tissue dissection and can even be performed percutaneously when necessary.

We analyzed 61 cases with varus deformity that were intraoperatively treated using this technique. In 4 other cases the technique was used as a percutaneous procedure in order to correct postoperative medial tightness. The procedure was considered successful when 2–4mm mediolateral joint line opening was obtained in extension and 2–6mm in flexion. In 62 cases (95%) a progressive correction of medial tightness was achieved according to the above described criteria. We therefore consider needle puncturing as an effective and safe technique for progressive correction of MCL tightness during minimally invasive TKA.

Introduction

Most of the algorithm available today to balance varus knee is based on a surgeon's hands-on experience without full understanding of pathological anatomy of varus knee. The high-resolution MRI allows us to recognize the anatomical details of the posteromedial corner and the changes of the soft tissue associated with the osteoarthritis and varus deformity. We have in this study, reviewed 60 cases of severe varus knee scheduled for TKR and compared it to normal MRI and those MRI were evaluated and read by a musculoskeletal radiologist. We have documented clearly the changes that happens in soft tissue, leading to tight medial compartment. We will also show multiple short intra-operative video confirming that MRI findings.

Purpose:

We compared patients, (group A) who had severe varus deformity with posterolateral varus thrust, with patients,(group B) who didn't have varus thrust for results of total knee arthroplasty.

Introduction

The hip-knee-ankle (HKA) angle between the mechanical axis of the femur (FM) and the mechanical axis of the tibia (TM) is the standard parameter to assess the coronal alignment of the lower extremity. TM is the line between the center of the tibial spines notch (Point T) and the center of the tibial plafond. However, this theory is based on the premise that TM coincides the anatomical axis of the tibia (TA). Fig.1a shows typical varus knee with medial shift of the tibial articular surface. In this case, TM does not coincide TA. Fig. 2 demonstrates the error of HKA angle when Point T locates medial to TA. Fig.2a shows normal alignment. Fig.2b shows varus alignment. Fig. 2c shows the tibia with medial shift of the tibial articular surface. The tibia has 7 degrees varus articular inclination in Fig.2b and 2c. However, HKA angle is 0 degree in Fig.2c. HKA angle underestimates varus deformity in knees with medial shift of the tibial articular surface. However, the degree of medial shift of the tibial articular surface is obscure. In this study, detailed anatomical configuration of the proximal tibia was evaluated. The effect of the value of HKA angle on the coronal alignment in TKA was then discussed.